1. Field of the Invention:
This invention relates generally to a dielectric ceramic composition and, more particularly, to a dielectric ceramic composition useful for use in microfrequency regions.
2. Description of the Prior Art:
With recent development of communication networks, the frequency of radiowaves utilized is extended to cover the microwave regions. In connection with this, dielectric ceramics are finding their applications in dielectric resonators, microwave integrated circuit substrates and impedance matching of various microwave circuits. Especially, there is an increasing demand for dielectric ceraics suitable for use in frequency stabilization of filters, gus and FET microwave oscillators.
Known dielectric ceramic materials for use in high frequency regions include ZnO.sub.2 -SnO.sub.2 -TiO.sub.2 ceramics, BaO-TiO.sub.2 ceramics and their derivatives modified with other metal oxide or oxides. The known ceramic materials, however, are not entirely satisfactory, because of their low unloaded Q values, low specific dielectric constant or incapability of providing desired temperature characteristics.